Apparatus for coating internal surfaces of hollow glassware



R. A. KUEBLER APPARATUS FOR COATING INTERNAL SURFACES OF HOLLOWGLASSWARE Feb. 19, 1952 2 SHEETS-SHEET 1 Filed March 27, 1948 w wkwv oAQ T T Lab VFW 1mm s 00 U v b Feb. 19, 1952 R. A. KUEBLER APPARATUS FORCOATING INTERNAL SURFACES OF HOLLOW GLASSWARE 2 SHEETS-SHEET 2 FiledMarch 27, 1948 m H e Wm .OKMAQ W i e w VT W 1mm .5 O R v Patented Feb.19, 1952 APPARATUS FOR COATING INTERNAL SURFACES OF HOLLOW GLASSWARERobert A. Kuebler, Cleveland Heights, Ohio, as-

signor to General Elect ration of New York ric Company, a corpo-Application March 27, 1948, Serial No. 17,494

6 Claims. (Cl. 11848) My invention relates to a method and apparatus forcoating the inner surface of hollow glassware for illuminating andirradiating purposes. More particularly my invention relates to a methodand apparatus for causing the generation of a fume or smoke oflight-diffusing or irradiation-modifying particles and for causing thedesired deposition of said particles over the inner surface of hollowglassware. My invention has most particularly to do with the depositionof a fume-produced diffusing coating upon the inner surfaces of the neckand bulbous portions of the envelopes of incandescent lamps. I

According to the invention of Marvin Pipkin, as disclosed in the pendingpatent application Serial No. 878, filed January 7, 1948 which is nowPatent No. 2,545,896 of March 20, 1951 which is assigned to the assigneeof the present invention, a fume or smoke of very fine particles is apreferred source of coating material for irradiation-modifying purposes.The fineness and character of the particles comprised of such a fume orsmoke are such as to cause them to adhere to glassware in a verysatisfactory manner when deposited directly out of the fume and are suchthat they can readily be deposited on glassware in a coating of apparentuniform density. For instance, the burning of a combustible siliconcompound such as ethyl silicate in a lamp bulb in the presence of airand oxygen produces a fume of very fine silica particles which aredeposited on the inner surface of the bulb to form a thin adherentcoating of very high diffusion characteristics and inappreciablelight-absorbing properties. The fume-produced coating can also beapplied to the inner surface of inside frosted incandescent lamp bulbsto give maximum difiuman.

One object of my invention is to provide a method and apparatus forproducing a fume of very fine light-diffusing or irradiation-modifyingparticles within hollow glassware and causing said particles to bedeposited on the inner surface of said glassware. The fume is producedby the flame from a burner inserted into the glassware and is theproduct resulting from the burning of a combustible silicon compound inthe presence of oxygen supplied in a minor proportion by the air withinsaid glassware and in a major proportion by a discharge from the burner.

Another object of my invention is to provide a method and apparatus forproducing a fume of very fine particles within hollow glassware ofvarying configuration and for varying the quantity of fume produced invarious portions of the glassware in conformity to the configurationthereof to effect the desired density of deposition of the fumeparticles in said portions. The control of the deposition of the fumeparticles is largely dependent on the circulation of the fume across theinner surface of the glassware and the period of dwell of thefume-producing burner in the various portions of said glassware.

Another object of my invention is to provide a method and apparatus fordirecting a fume of very fine particles against the surface of glasswarein a manner causing'said fume to effectively impinge upon or wipe saidsurface. Such a manner of operation permits very satisfactory controlsto be established over the density of the deposition of the fumeparticles and gives maximum economy, high efllciency and high speed ofmanufacture. The fume is produced within the flame from a burnerintroduced into the hollow interior of the glassware, which flameresults from the burning of a combustible fumeproducing gas dischargedby said burner and which extends in a lateral direction from said burnerbecause of the pull or suction of a stream of a second gas dischargedwith some force contiguously thereto. Almost all of the fume appears inthe stream of gas and is discharged in the direction of and with theforce of said stream so that a selective distribution of fume about theburner results. A relative movement between the burner and the glasswarepermits the desired distribution of fume particles over the surface ofsaid glassware. The directional properties of the burner are desirableto provide a ready control over the distribution of the fume particlesover the glassware and permit uniform, very light and graduateddepositions thereof over various portions of said glassware.

Still another object of my invention is to provide a, burner for thepropagation of a fumeproducing flame, which burner generates withinitself the gas burned in the flame from a liquid supply and whichaffects said generation by absorbing heat from the flame andtransferring it to said liquid. The self-generating burner is also ofsuch proportions as to be capable of proper operation within therelatively confining open neck and the adjacent comparatively large bulbous portion of a glass lamp bulb or other glassware and accordinglymust not cause such nonuniform heating of the bulb or glassware thatcracking occurs, and must cause the desired deposition of fume particlesover relatively great variations in area. The burner must also assist 3in controlling the burning so that a fume of particles of the desiredsize and character is produced and a sufficiently large quantity of fumeis produced to allow the rapid and economical coating of glasswarewithout creating explosive conditions in said glassware.

Still another object of my invention is to provide a burner for thepropagation of a fumeproducing flame, which burner is so constructedthat a minimum of fume particles deposit thereon, and which is readilycleaned of deposit. Still further objects and advantages of my inventionwill appear from the following description of species thereof and fromthe drawing.

In the drawing, Fig. l is a side elevation of a burner and associatedapparatus for the propagation of a fume of fine light-diffusingparticles and for causing said fume particles to deposit in a selectedmanner over the inner surface of a lamp bulb, the apparatus being shownmidway through a cycle of operation and partially broken away in theplanes of a quarter section; Figs. 2 and 3 are sectional plan and sideviews, on an enlarged scale, of the burner disclosed in Fig. 1; Fig. 4is a side elevation, from which a quarter section is taken, of a commonform of lamp bulb, a burner and directly associated apparatus forcausing fume particles to deposit on the inner surface of said bulb;Fig. is a sectional plan view of the burner disclosed in Fig. 4 as takenfrom the plane indicated by the line 55 in Fig. 4 and in the directionindicated; and Fig. 6 is a sectional view, on an enlarged scale, of amodifled burner.

The specific form of my invention appearing in Figs. 1, 2 and 3 startsits cycle of operation with the burner I and the bulb holder 2 in alowered position with their upper ends only slightly above the topsurface of the support bracket 3, at which position sufficient clearanceis provided below the conveyor 4 to allow lateral movement of saidconveyor 4 to advance the lamp bulb 5 to the position shown. Theconveyor 4 can take the form of a turret or any other well-known form ofcarrier; however, it is preferred that it be driven from the drive shaft6, which also provides the means of timing and effecting all operationsof the coating apparatus, in order to function in proper synchronismtherewith. If less automatic operation is adequate or desired, theconveyor or holder 4 may remain in the position shown at all times andthe lamp bulbs 5 may be inserted and removed therefrom manually at theproper intervals.

All operations of the coating process occur at the work station shownand are initiated, after the lamp bulb 5 is located at said station, bythe upward movement of the holder 2 and the burner I. These movementsare brought about by the rotation of the drive shaft 6 and the cams 9and III, the former of which raises the holder 2 until it engages theinner surface of the bulb neck I and, through said engagement, lifts thebulb 5 from the rests 8 of the conveyor 4, and the latter of whichraises the burner I into the bulb 5 through its neck I. At the presentlydescribed moment the high side of the cam 9 is brought into positionbelow the roll-er II on the lever I2 thereby causin said lever I2, whichis connected to the lower end of the holder 2 by means of link l3 andcollar I4, to turn about the stationary shaft I5 to thereby raise saidholder 2. The collar I4 is a split member in which the holder 2 can turnfreely and can only influence the vertical position of the holder sincethe only positive tionary shaft I5 so that the link I9 and collar 20,

which connect it to the metal burner support tube 2|, are moved upwardand effect a corresponding movement in the suppcrt tube 2I and burner I.

At the time the burner I and shield 22 are introduced into the neck I ofthe bulb 5, the upper end portion of the burner is located just abovethe top of the tubular metal shield 22 which is in effect the upper endof the holder 2, and a flame burns about a discharge opening completelyaround said end portion. The flame results from the combustion ofgaseous ethyl silicate discharged laterally from between the metalshield or cap 23 (Figs. 1, 2 and 3) and the flanged metal head 24 of theburner l and is drawn into a contiguous stream of gas dischargedlaterally or radially from the openings 25 in the base of the peripheralgroove 26 about the burner head 24.

The base of said groove 26 is formed by a depending annular flange orring portion 26a. of the head 24. Only a minor portion of the flameremains out of the stream of gas as the pressure of discharge of thegaseous ethyl silicate is relatively low since it is free to passthrough the large openings 21 in the tubular stem portion 210. of theshield 23 as soon as it is generated from the liquid form L present inthe stem 23 of the burner I.

Control over the amount of the combustible ethyl silicate gas dischargedby the burner I is afforded through the control of the liquid ethylsilicate introduced into the burner I, which liquid is drained by theforce of gravity from a constant level reservoir 29 through the valve 30and the flexible hose 3| to the lower end of the support tube 32 onwhich the stem 23 of the burner I is mounted. The control valve 38 isadjusted to allow the required quantity of liquid ethyl silicate to flowinto the stem 28 of the burner I to produce the desired flame thereaboutand has no reference to the ability of the burner I to generate gastherefrom. The liquid level in stem 28 should not be permitted to falltoo low since that would cause the vapors to burn inside the cap portion21a and thereby fill up the holes 21. For all normal requirements of theburner I, suflicient heat is contained therein to vaporize the liquidethyl silicate as fast as it is introduced into said burner I, althoughthe level of the liquid ethyl silicate in the burner I rises as greateramounts thereof are fed thereto. To retain the proper degree of heat inthe burner, the stem 28 may be made of metal having relatively poor heatconductivity; a suitable material is a stainless steel containing about18 per cent chromium, 8 per cent nickel and the remainder iron. Thesleeve 35 and cap 23 may be made of the same material, or the said capmay be made of brass. An inverted bottle 33 with its open neck in thereservoir 29 provides the automatic means of replenishing the liquiddrained therefrom.

The stream of gas discharged iron the openings 25 in the burner I is atsuch a pressure that the major part of the gaseous ethyl silicate isdrawn into it and produces a flame taking the same direction as thestream. It is preferred that the gas in said stream be oxygen so as tofacilitate the formation of fume particles of the desired character fromthe flame and accordingly a source thereof (not shown) is connected tothe rubber hose 34 leading to the outer support tube 2| which isconnected by means of the sleeve 35 of the burner I to the openings 25therein. An adjustable conis constantly being rotated by the holder 2.

The rotation of the bulb 5 is also desirable to cause the full peripherythereof to be uniformly heated by the flame so as to avoid cracking saidbulb, and is effected through its engagement with the refractory collar36 on the holder 2. The said collar 36 fits snugly in the neck 1 of thebulb 5 and may be made of a mixture of asbestos and Portland cement. Therelatively light engagement of the shield 22 with the bulb neck 1assists in keeping the bulb 5 in alignment with the holder 2 during therotative movement which is imparted to said holder 2 from the pulley 31by means of the key 38 therebetween. The pulley 31 is driven from asource (not shown) of constant rotation by means of the belt 39 and isretained in the position shown, so as not to be affected by the verticalmotions of the holder 2, by the key 40 which is fastened to the supportbracket 3 and which enters a peripheral groove in said pulley 31. Thekey 38 slides in a longitudinal keyway in the holder 2 during thevertical movement thereof.

The deposit of fume particles on the bulb 5 is restricted, at a giveninstant, largely to the area of the bulb 5 contacted by and adjacent tothe stream of gas emitted by the burner I, as nearly all of the fume ispr'o'duced in the stream of gas and to a great extent deposits on saidbulb 5 during its wiping engagement therewith. The stream of gas emittedby the burner I becomes in effect a stream of fume which, afterengagement with the walls of the bulb 5, rolls both up and down alongsaid walls bringing all of the fume particles therein into engagementwith the said walls. The undeposited fume of the gas stream combineswith the very small amount of fume given off by the portion of the flameoutside said stream and circulates throughout the bulb 5 until it isfinally exhausted to the atmosphere, together with other products ofcombustion, through the open upper end of the holder 2 and the lateralopenings 4| therein. The portion of the flame outside of the gas streamburns slowly in a flickering manner and has the dual function ofcontributing heat to the burner I and of piloting the flame within thegas stream.

The rate of production of fume by the burner I is so hi h that theupward movement thereof need not be interrupted after it first entersthe open neck I of the bulb 5 and is caused to continue, although atsomewhat less speed. When the burner I is raised to the position wherethe stream of fume therefrom passes beyond the narrow neck 1 of the bulb5 and into the wider flaring portion of said bulb 5. its rate ofmovement is reduced proportionately to the greater area, over which thefume particles are deposited so that a short inactive period in themovement of the burner I when the stream of fume therefrom reaches theupper limit over which the fume particles are to be deposited on thebulb 5 in the present instance. The bulb 5 is to have a substantiallyuniform coating of fume particles over the neck and side walls thereof,with a very light coating on the top end or face thereof. Therefore, theburner I is again caused to move down after a time interval at the upperlimit of its motion during which a coating is built of equal density tothat deposited over the other portions of the bulb 5 during the upwardmovement of the burner I and the subsequent return downward movementthereof. The shape of cam I0 is such that the downward movement of theburner I is more rapid than the upward movement because the bulb 5 washeated during the upward movement of the burner I and now cannot besubjected to the same degree of heat without softening or melting.

When the burner I has been lowered to a position where the gas streamjust passes the top of the shield 22, a corresponding downward movementoccurs in both burner I and holder 2 which first lowers the bulb 5 ontothe rests 3 of the conveyor 4 and then carries the burner and holdercompletely out of the neck 1 of the bulb 5. The conveyor 4 then indexesso as to carry the coated bulb 5 out of the work station and bringanother uncoated bulb in its place.

The upper end of the bulb 5, which receives a coating of very lightdensity, is in the present instance coated by particles from theextraneous fume within the bulb 5 and gradually increases in densityaround the edge to the full density of the side coating on said bulb 5due to the additional deposit of fume particles from the fume stream atthis point. The shield 23 over the top of the burner I is to a certainextent responsible for the extremely light density of the coating on theend of the bulb 5 in that it prevents the combustible fume-producing gasfrom burning over the upper end thereof; however, almost any degree ofdensity can be obtained by varying exposure of the fume thereto. In thepresent instance the reduction in exposure to the fume is effected bygiving the burner I directional properties which permit more readycontrol of the distribution of the fume, by shielding (shields 22 and23) the fume from portions of the bulb 5, and by varying the length oftime to which various portions of the bulb 5 are exposed to the fume. Toproduce a deposit of uniform density over glassware of varyingconfiguration it is preferable that the burner produce fume at a uniformrate and the rate of movement of the burner be inversely prov portionalto the area covered by the stream of fume therefrom. In every instance,however. it is preferred that that portion of the glassware to be coatedbe lifted from engagement with any supporting means or held in somemanner whereby said means cannot have a cooling effect thereon andaccordingly disturb the disposition of fume or heating of saidglassware.

If other glassware of different shape and proportions, such as thecommon form oi lamp bulb shown in Fig. 4, is to be coated uniformly overthe entire interior surface thereof, a modified burner i is preferablyused. The fume particles are to be deposited over the end and the sidesof the bulb 5' so that the ability of burner l' to direct a stream offume both laterally and longitudinally thereof is preferable.

The combustible fume-producing material is introduced into the burner Iin liquid form L through the bottom of the support tube 3 2 and isvaporized into a gas by the heat within the stem 28' to finally bedischarged out the openings 21 of the shield or cap 23'. The (oxygen)gas stream establishes the direction of spread of the fume-producingflame and, accordingly, the stream of gas enters the sleeve 35' of theburner I from the support tube 2| and is discharged from the burner Ithrough the openings 25 (Figs. 4 and 5) located in the base of theperipheral groove 26' in the stem head 24'. The assembly of parts makingup the burner i is completed by a deflector 43 consisting of a deflector43 consisting of a sheet metal ring having an oblique upper end 43'. Thesaid deflector 43 is the means of redirecting the gas stream from theopenings 25' so that it passes directly from the openings 25 in alateral direction at one (low) side of the deflector (which is below theopenings) and is redirected and takes a more upward direction furtheraround said burner I until a vertically upward direction is taken at theopposite (high) side of the deflector which is above the openings 25'.

The above-described modified burner I is preferably used in combinationwith apparatus like that shown in Fig. l and effects the coating of thelamp bulb 5' while said bulb is supported and rotated by a holder 2'corresponding to the holder 2 of the Fig. l apparatus. At the start ofthe cycle of operation the burner I is located just above the top edgeof the shield 22' and is moved upward toward the top end of the bulb 5'at a variable rate of speed to a great extent dependent on the areaswept by the stream of fume emitted thereby. In the present instance,there is more extraneous fume in the bulb 5' than in the Fig. 1apparatus since the flame and, consequently, the fume directed upward inthe gas stream from the burner i, is initially a relatively longdistance from the top of said bulb 5' and since a larger proportion offlame burns freely over the top of said burner l and outside of the gasstream. This extraneous fume is responsible for a larger amount of thefume particles deposited on the bulb 5' than in the prior instance;however, the desired uniformity of coating is obtained if the burner Iis moved upward and then downward in said bulb 5 during the cycle ofoperation in much the same manner as in the prior instance. A shortdwell occurs in the movement of the burner l at the upper limit thereof;otherwise, it is uninterrupted. The burner I is also characterized byrelatively thin walls of the stem 28 and the sleeve 35' in order toreduce the heat loss therefrom to a minimum.

The modified coating burner 45 shown in Fig. 6 is adapted to project anupwardly and outwardly directed stream of fume from the end thereof, astream which is particularly desirable in coating long tubular glasswarebut which is likewise useful in coating a lamp bulb like that shown inFig. 4. The combustible fume-producing liquid L is vaporized into a gasin the head 48 of the burner 45 and flows through a plurality oi lateralopenings 48 to an inverted irusto-conical or outwardly flaring annulardistribution chamber 49 vented at the edge of the burner head 45. The(oxygen) gas stream developing the directional properties of the burner45 is discharged from the opening between the upper edge of the burnerhead 46 and the surrounding outer shell 50 of said burner 45 and passesupward and outward between the upper edge 5| of the shell 50 and theshield or deflector 52 mounted thereabove. The flame is flared outwardlyand has a swirling motion caused by the circulation of the stream of gasabout the screw-shaped (helical) partition 53 between the burner head 46and the shell 50. Both flame conditions assist in causing the fumeproduced thereby to wipe or scrub the surface of the glassware. Thesources of the combustible liquid and the gas are connected to thesupport tubes 54 and 55, respectively, of the burner 45, the liquidflowing upward through the open interior of the tube 54 and the burnerhead 46, and the gas flowing through the space between tubes 54 and 55,and the grooves 56 in said head 45.

In normal operation some particles of fume deposit on the burner 45 andmust be brushed therefrom on occasion, while at other times a morethorough cleaning of said burner 45 is required. The normal passage ofthe gas stream up between the tubes 54 and 55. through the grooves 56and between the burner head 45 and the shell 50 keeps these portions ofthe burner 45 clean. Those portions of the burner 45 holding both theliquid and gaseous combustible material are, on the other hand, subjectto blocking by particles deposited from the fume and are constructed soas to be readily removable for cleaning. The shield 52 and the cap 51can be lifted from the burner 45, thereby giving access to the fulllength of the interior of the burner head 46 and the support tube 54,the openings 48 and the distribution chamber 49. Replacing the shield 52and the cap 51 merely consists in first lowering the cap 51 over thetubular projection 58 within the well 62 in the top of the burner head46 to the extent allowed by the shoulder 59 and then inserting the post60 extending from the shield 52 into the opening provided by the tubularprojection 6| on the cap 51 to the extent allowed by the projection 58.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Apparatus for coating the inner surface of a lamp bulb with particlesof a fume comprising a vertically reciprocable burner having means fordischarging a combustible fume-producing gas and having contiguous meansfor directin a stream of combustion-supporting gas closely adjacent theflame of the burning fume-producing gas whereby to draw a major portionof the said flame into said stream of combustion-supporting gas, aconveyor having support rest means to support the lamp bulb in uprightrested position thereon with its open neck and down, said conveyor beingmovable to advance said support rest means to a position directly oversaid burner to vertically align the bulb therewith, a bulb holdermounted in substantially vertical alignment with said burner, supportmeans mounting said bulb holder for rotation about its vertical axis andfor vertical reciprocation independently of said burner, means forrotating said holder, actuating means operatively connected to saidburner and holder to first raise them concomitantly in their normalelevational position relative to each other to elevate said holder intoengagement with the neck of the bulb and lift it to a predeterminedposition off said support rest means and to then elevate said burnerrelative to said holder a further amount to introduce the burner intothe bulb on said holder and cause the fume therefrom to deposit acoating of fume particles onto the interior surface of said bulb, saidactuating means being further operative to thereafter lower the burnerrelative to said holder to its normal elevational position relativethereto and then concomitantly lower both said burner and holder totheir initial lowered position to lower the bulb onto said support restmeans and disengage the holder from the bulb and withdraw said burnercompletely from the interior of said'qbulb, and operating meansconnected to said actuating means and said conveyor to operate them inproper time relation with each other.

2. Apparatus for coating the inner surface of hollow glass articles ofthe open neck end type with light-diffusing particles ofa fumecomprising a vertically extending holder engageable at its upper endwith the interior surface of the article neck to support the articleupright with its neck end down, a burner comprising a cylindrical stemportion extending vertically through said holder and provided, with aburner head at its upper end, said burner stem having separatepassageways therethrough respectively connected at their lower ends to asource of a vaporizable liquid fume-producing fuel and a source ofcombustion-supporting gas, and said burner head having a heat-retainingcapacity proportioned to vaporize the liquid fuel at a point interiorlyof the burner head during the normal operation of the burner and havinga discharge outlet for discharging the vaporized fuel at relatively lowvelocity from the burner head and openings for discharging a stream ofsaid combustion-supporting gas contiguous to the discharged fuel vaporwhereby to mix therewith to effect the combustion thereof into a shortflame extending laterally out from the burner head and draw a majorportion of the burning fuel vapor into said stream ofcombustion-supporting gas to cause the resulting stream of fume toimpinge on the inner surface of the article, and actuating meansconnected to the lower end of said burner stem for vertically moving theburner head through the interior of the article to distribute the fumeparticles over the desired portion of the inner surface of the article.

3. Apparatus for coating the inner surface of hollow glass articles ofthe open neck end type with light-diffusing particles of a fumecomprising a vertically extending holder engageable at its upper endwith the interior surface of the article neck to support the articleupright with its neck end down, support means mounting said holder forrotational movement about its vertical axis, a burner comprising acylindrical stem portion extending vertically through said holder andprovided with a burner head at its upper end. said burner stem havingseparate passageways therethrough respectively connected at their lowerends to a source of a vaporizable liquid fume-producing fuel and asource of combustion-supporting gas, and said burner head having aheat-retaining capacity proportioned to vaporize the liquid fuel at apoint interioi'ly of head and draw a major portion of the burning.'.fuel vapor into said stream of combustion-supporting gas to cause theresulting stream of fume to impinge on the inner surface of the article,

means connected to said holder for rotating it about its axis, andactuating means connected to the lower end of said burner stem forvertically moving the burner head through the interior of the article todistribute the fume par-,

ticles over the desired portion of the inner surface of the article.

4. Apparatus for coating the inner surface of hollow glass articles ofthe open neck end type with light-diffusing particles of a fumecomprising a vertically extending holder engageable at its upper endwith the interior surface of the article neck to support the articleupright with its neck end down, support means mounting said holder forrotational movement about its vertical axis, a burner comprising acylindrical stem portion extending vertically through said holder andprovided with a burner head at its upper end, said burner stem havingseparate passageways therethrough respectively connected at their lowerends to a source of a vaporizable liquid fume-producing fuel and asource of combustion-supporting gas, and said burner head having aheat-retaining capacity proportioned to vaporize the liquid fuel at apoint interiorly f the burner head during the normal operation of theburner and having an outlet for discharging the vaporized fuel atrelatively low velocity laterally from the burner head and having ashield thereover for preventing the fuel vapor from burning over theupper end of the burner and for restricting the endwise distribution offume therefrom, said burner head further having means defining a chamberhaving an outlet contiguous to the fuel outlet for discharging a streamof the combustion-supporting gas laterally from the burner head andcontiguous to the discharged fuel vapor whereby to mix therewith toeffect the combustion thereof into a short flame extending laterally outfrom the burner head and draw a major portion of the burner fuel vaporinto said stream of combustion-supporting gas to cause the resultingstream of fume to impinge on the inner surface of the article, meansconnected to said holder for rotatin it about its axis, and actuatingmeans connected to the lower end of said burner stem for verticallymoving the burner head through the interior of the article to distributethe fume particles over the desired portion of the inner surface of thearticle.

5. Apparatus for coating the inner surface of hollow glass articles ofthe open neck end type with light-diffusing particles of a fumecomprising a vertically extending tubular holder engageable at its upperend with the interior surface of the article neck to support the articleupright with its neck end down, support means mounting said holder forrotational movement about its vertical axis, a burner comprising a headat its upper end, said holder having an internal bearing supporting theburner for vertical reciprocation and providing for rotational movementof the holder about its axis relative to said burner, said burner headhaving openings for discharging a combustible fume-producing gastherefrom and having other openings for discharging a stream ofcombustion-supporting gas contiguous to the discharged fume-producinggas whereby a major portion of the flame of the burning fume-producinggas is drawn into said stream and the resulting fume caused to impingeon the inner surface of the article. a source of a vaporizable liquidfume-producing fuel and a source of combustion-supporting gas connectedto the lower end of said burner stem in communication with separatepassageways extending therethrough and respectively connected at theirupper ends to the said openings in the burner head, means connected tosaid holder for rotating it about its axis, and actuating meansconnected tto the lower end of said burner stem for vertically movingthe burner head through the interior of the article to distribute thefume particles over the desired portion oft-he inner surface of thearticle.

6. Apparatus for coating the inner surface of hollow glass articles ofthe open neck end type with light-diffusing particles of a fumecomprising a vertically extending tubular holder engageable at its upperend with the interior surface of the article neck to support the articleupright with its neck end down, support means mounting said holder forrotational movement about its vertical axis, a burner comprising acylindrical stem portion extending vertically through said holder andprovided with a burner head at its upper end,-said holder having aninternal bearing supporting the burner for vertical reciprocation andproviding for rotational movement of the holder about its axis relativeto said burner, said burner head having openings for discharging acombustible fume-producing gas therefrom and having other openings fordischarging a stream of combustion-supportingv gas contiguous to thedischarged fume-producing gas whereby a major portion of the flame ofthe burning fume-producing gas is drawn into,

said stream and the resulting fume caused to impinge on the innersurface of the article, a source of a vaporizable liquid fume-producingfuel and a source 01 combustion-supporting.gas connected to the lowerend' of said burner stem in communication with separate passagewayrextending therethrough and respectively connected at their upper ends tothe said openings in the burner head, means connected to said holder forrotating it about its axis, and actuating means connected to the lowerend of said burner stem for moving the burner head upwardly through theinterior of the article and then retracting it downwardly out of thearticle to effect the desired distribution of the fume particles overthe inner surface thereof, said actuating means being arranged toretract said burner downwardly at a substantially greater rate ofmovement than it advances the burner upwardly into the article wherebyto avoid overheating of the latter.

ROBERT A. KUEBLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

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